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Physical & Chemical properties

Vapour pressure

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Description of key information

=< 5.6 Pa at 20 °C 

Key value for chemical safety assessment

Additional information

Calculation at 50 °C: =< 100 Pa.

The vapour pressure was determined with the use of Grain-Watson estimation as outlined in the OECD Guildeline 104. The experimental result of the DSC method was not in the appropriate validity range with respect to this method. The calculation is based on the lowest possible boiling temperature, which in fact is probably a decomposition temperature. In a peer reviewed SIDS Initial Assessment Profile (SIAM 25, 17 -18 October, 2007) it is stated that: "As ionic substances, all members of this category have extremely low vapour pressures. Calculated values are in the ranges 1E-11 hPa to 1E-15 hPa (C8 -18 alkyl sulfates) (...) Therefore, they decompose before reaching their theoretical boiling points". Thus, the obtained value should be considered an upper limit of the vapour pressure and accepted for the risk assessment calculations in the sense of a "worst-case scenario". The same holds for the value calculated at 50 °C.